Green is a relatively new colour in cats and has not yet been
seen on the showbench. Breeders have been working to understand the
genetics of this colour since it first appeared in stray cats in
1995 and 1996, with a view to developing a green breed. This could
then be used as an outcross in order to introduce the colour into
existing breeds. The working name for the breed is "Danish Green"
since the first green cat occurred in Denmark. None of these photos are Photoshopped.

THE FIRST GREENS

The first green cat was born in
north-west Denmark in 1995. Named "Miss Greeny", the kittens was
found in a hayloft and it immediately caused a sensation. The
kitten's fur and claws were green and the colour could not be
washed out. The colouration was initially attributed to a mutation,
however a vet attributed it to a copper patina, apparently present
since birth, from the tip of its fur to the hair follicles. The
high copper content in the local water supply was apparently
causing a verdigris effect, but would normally be toxic. Miss
Greeny's unusual colour faded as new fur grew through, apparently
because she was no longer exposed to copper-rich water.

The appearance of Miss Greeny was
reported in newspapers and journals around the world.

COPENHAGEN, Denmark (AP) -
Something's green in the state of Denmark. It's a kitten, much to
the puzzlement of veterinarians who've tried to wash out the cat's
grass-green tint.

"Experts from the university
hospital said that the colour also appears in the hair follicles,"
Pia Bischoff, the kitten's owner, said Monday. "It could be a
metabolism defect."

The two-month-old feline, called
Miss Greeny, is all green except for a grey spot on the back, she
said. Samples of the kitten's green hair have been sent to
Copenhagen's university hospital for testing. Other than the
unusual shade, Miss Greeny is a normal, frisky feline.

"She is bobbing around, playing
and being adorable like all other kittens," said Bischoff who lives
in Dybvad, 160 miles northwest of
Copenhagen.

DYBVAD: Puss cats come in various
sizes and many hues, but never green. That is, until Miss Greeny, a
verdigris-colored Manx-blend kitten, was born 2 months ago in a
hayloft in this Danish town. Researchers at Copenhagen University
hospital who have inspected fur samples say even the follicles are
pigmented, indicating that the color comes from within. Says Knud
Steensborg, a local veterinarian who has examined Miss Greeny: " At
first I suspected a prank. But there's no doubt: this is a
zoological sensation." Steensborg believes the odd coloration is
the result of a disorder in the kitten's copper
metabolism.

On 26th November 1995,
five-year-old Kristinne Bischoff appeared with Miss Greeny during a
six-hour weekend appearance at the Denmark's Aarhus Natural History
Museum. Danes packed the museum to get a glimpse of the green
kitten.

By 1996, having appeared at cat
show and other venues, the kitten apparently vanished from the
public gaze.

To the surprise and delight of cat
fanciers, although Miss Greeny's green colour initially appeared to
fade, as her adult coat grew in, the colour intensified. Further
analysis of hair samples showed that the colour was due to mutated
pigment cells in the hair rather than by a patina of copper as
initially thought. By that time, though, Miss Greeny had been
spayed and the gene appeared to be lost. Due to the cat's
temperament, her owner decided not to exhibit her unique pet again.
There were further reports of green kittens in 1995 and 1996,
including one in the Netherlands, but none were
authenticated.

A year after Miss Greeny's birth,
her barn cat mother, had produced further unusually coloured
kittens, presumably fathered by Miss Greeny's father (the dominant
male in the area at that time). Of the three kittens (one
stillborn), two male kittens had the same distinctive green colour
as Miss Greeny. The intention was to test-mate one of these to Miss
Greeny, but she had already been spayed. The two kittens were
adopted by an English cat fancier Maria Goddard who worked at
Copenhagen University. Mrs Goddard also adopted their mother in
order to mate the male kittens back to her. She attempted to trap
the presumed sire, but he was later found dead on a nearby
road.

As with Miss Greeny, the colour of
the two green males initially faded before growing back with
greater intensity. The one with the best developed colour, "Mister
Greeny" (Herr Grünlich), was mated to his mother in 1997,
producing two litters. Among the kittens was an intensely green
female whom Mrs Goddard named "Grunhilde". The other male kitten
from the original litter, Loki, was acquired by Mrs Agnetha
Fredrikson to be test mated to other cats to determine the mode of
inheritance. By using purebred cats of known genotypes (i.e.
breeders knew what genes their cats carried and for which colours)
she could determine whether green operated as a new colour entirely
or as a modifier of other colours. He was mated to a variety of
longhair and shorthair females, giving rise to selfs, tabbies,
smokes and tipped cats. Many of his progeny played important roles
in the later breeding program.

Mrs Goddard's Grunhilde and her
half-brother Loki were to become the founders of a line of green
cats. Mrs Goddard realised she had two main choices: develop a
breed which bred true for the green colour or permit her green cats
to be used as outcrosses for other breeds into which the new colour
could be introduced. She was well aware that a Green Persian would
be particularly attractive. She decided initially to develop the
cats as a true-breeding strain, using European Shorthair outcrosses
to improve conformation and in order to understand the genetics of
green. Much of the genetics groundwork had already been done by
Fredrikson.

If green operated as a new colour
carried on the same allele (section of DNA) as an existing colour,
it would either be dominant to, or recessive to, that existing
colour. For example it might be a genetic alternative to black (a
mutant version of black). Most genes are inherited in pairs. If it
was a dominant gene, the cat only needed to inherit one copy of the
gene to give it the green colour. If it proved to be recessive, a
cat had to inherit two copies of the gene to be a green cat (the
complication is that there are several genes on the black allele
and some genes are more dominant than others in a sort of sliding
scale effect).

If it was a modifier, it would be
carried on a different allele. The best example is the dilute
modifier. If a black cat inherits the dilution gene alongside the
black gene, you get a blue (grey) cat. If a red tabby cat inherits
the dilution gene alongside the red gene, you get a cream tabby
cat. Dilution gives a washed out version of the cat's colour. If it
was a modifier, it might cause different shades of green depending
on what other colour genes the cat inherited. For example, it might
modify black into dark green, grey into light green.

These are all considerations which
any breeder has to bear in mind when developing a new trait - how
that trait is inherited and how it interacts with other
traits.

NOT GENETICALLY MODIFIED

When the green cats were first
exhibited, some cat-lovers accused breeders of dabbling with
genetically modified (GM) cats and cited the examples of "CC" the
cloned kitten (cloning is not the same as GM) and fluorescent white
rabbits produced by inserting a jellyfish gene into a fertilized
rabbit ovum.

Breeders emphasise that the green
cats are neither GM nor clones, but were developed from a chance
mutation in exactly the same way as breeds such as the Munchkin. GM
is expensive and currently limited to laboratory animals and
experimental livestock. Following the GM fluorescent rabbit,
magazines frivolously suggested possibilities such as calico cats
with red, black and fluorescent patches. Mutations occur all the
time, but relatively few are viable and even fewer are both
harmless and eye-catching.

"Only the colour is affected,"
says American breeder Robin Schmidt, "As far as anyone can tell,
this mutation has no side-effects. People are naturally sceptical
because it's so different to what they are used to seeing in terms
of feline colouration. When Siamese cats first arrived in the West,
they were described as nightmarish and unnatural because they were
very different to the common perception of what a cat should look
like, but they were everyday cats in Thailand! In twenty years'
time, no-one will give the new colour a second thought."

According to Andrea Thornton, who
owns two female green longhairs, the cats are completely normal.
"Mine have access to an outdoor run, and when they sit among the
shrubs it is impossible to see them. On several occasions I've been
certain they have escaped, only to find them sleeping between
bushes. My neighbour is convinced I've dyed them! I'm planning to
mate them this spring and I'm really looking forward to showing him
the kittens and proving that they really are born that
colour."

Dev Smith is another fan of the
green kitties. He owns Green Ginger, one of very few non-breeding
greens due to cryptorchidism (undescended testicles). "I was
forever explaining to friends that Green Ginger is naturally that
colour and that I haven't dyed his fur. They are divided into those
who think the colour is awful and those who want one just like him.
He's just a very sweet kitty who doesn't know what a stir he causes
when people see him."

Others are not so enthusiastic.
Some animal welfare workers have already spoken against breeding
the new colour, "People might try to dye cats green, either because
they can't afford the real thing or because there is money to be
made from selling fake green cats. We don't recommend using any
form of dye on cats because they are likely to lick it
off."

Andrea Thornton disagrees. She
says the same could be applied to any unusual or uncommon breed,
"It is ludicrous to say 'don't breed these cats'. The green gene is
out there, it is a recessive gene. Recessive genes don't go away,
they just stay hidden in the gene pool and pop up at a later
date."

INHERITANCE OF GREEN

Green appears to be a mutant
allele of black producing a green pigment called chloromelanin instead of eumelanin. It is recessive to both black and chocolate, but
has a more complex relationship with cinnamon. When green was mated
to cinnamon (cinnamon being homozygous), the offspring were a mix
of green and cinnamon selfs. This meant that green either carried
cinnamon as a recessive, or that the two genes were co-dominant
with respect to each other and that some other factor determined
which gene was expressed in heterozygous kittens. Alternatively, it
was possible that green could never occur in the homozygous state
(possibly the homozygote embryo fails to develop due to some lethal
factor).

Another peculiarity of
green is that it is not visibly affected by the maltese
dilution gene (that which turns black to blue). Cats whose genotype
includes the dilution factor are phenotypically the same as
non-dilute greens.

The dilute greens are, however,
visibly affected by the dilute modifier gene (better known as
caramel gene). The caramel version of green is a muddy, olive-green
colour which, in the words of Fredrikson "is curious, not
particularly attractive and has nothing to recommend
it".

ORIGINAL COLOUR

DILUTE VERSION (HOMOZYGOUS FOR
DILUTE)

CARAMELISED VERSION OF THE
DILUTE VERSION (DOUBLE DILUTION)

White

N/A

N/A

Black

Blue (Grey)

Caramel

Chocolate

Lavender (Lilac)

Taupe

Green

Green

Olive

Cinnamon

Fawn

??

Red

Cream

Apricot

Green and white
longhair. This cat shows excellent clarity of colour and a
"vibrant" green, but eye colour is "muddy".

Green self;
probably dilute green with dilute modifier (caramel) gene since the
colour is a murky olive green. The pale chin is a
fault.

Green-tabby-and-white bicolour female with green or green tabby
kittens. Green self kittens often have pronounced "ghost markings"
which fade by about 8 weeks of age. Green tabbies have poor
contrast of markings.

A well-coloured green self should
have an even grass green colour, with breeding preference given to
the more intense greens. At present there is much variation of coat
colour due to the effects of polygenes. Some appear slightly
yellowish due to red pigment appearing in the hairs. The appearance
of lockets in his progeny indicates that Loki carried a gene for
white spotting. The white bicolours (descended from Grunhilde) are
also attractive - cats with high levels of white are sometimes
described as appearing "grass-stained".

Thanks to early matings of Loki to
a variety of purebred females, some of the other green patterns had
already appeared. The Agouti green (classic tabby and mackerel
tabby) display a lack of contrast between the solid pattern colour
and the ticked background colour. The effect is described as
"flat". The introduction of the Inhibitor gene, however, gives rise
to attractive Green Silver Tabbies. These are particularly
eye-catching in the classic tabby pattern. In the silver tabbies,
breakthrough of red pigment (phaeomelanin) sometimes occurs, giving
the background colour a sickly yellow-green cast.

The Green Shaded Silver and Green
Chinchilla (genetically closely related to Green Silver Tabby) are
also visually appealing, particularly the delicately tipped
Chinchilla. The longhair Green Chinchilla is described as "a misty
green tint". In the Green Chinchilla and Green Shaded Silver,
orange eyes contrast better with the fur colour, so these would
more correctly be termed Green Pewter. In the Non-agouti form, the
Green Smoke is a darker cat with a pale undercoat, particularly
visible at the ruff and britches (area on the back of the legs,
just beneath the tail) where the hair tends to be woollier. Some of
the Lighter Smokes have very attractive green veiling over an
off-white undercoat.

Another interesting result of
green's resistance to the dilution gene is seen in tortoiseshell
and calico cats. Being an allele of black, green forms
tortoiseshells when in combination with the O (red) gene. The full
colour green tortie can be an eye-jarring mix of orange and green
(more precisely orange, cream and green since all red cats manifest
as tabbies). The dilute version, however, is more pleasing to the
eye. The dilution gene leaves the green unchanged, but turns red
into an attractive cream colour. These green-creams are attractive,
especially in combinaiton with the full coat of the
Persian.

The effect of the piebald gene
breaks up the brindled colours into distinct patches as described
inBeautiful Bicolours. The well-defined patches of the
green/red/white calico was nicknamed "The Crazy Quilt Cat" by
visiting American breeder Robin Schmidt, "Green and ginger just
doesn't go."

THE FUTURE OF GREEN
CATS

Although green has so far been
seen in solids, bi- and tri-colours, tabbies, smokes and
shaded/tipped cats, so far there have been no experimental green
colourpoints (Himalayan or Siamese pattern), green mink
(Tonkinese-type); or green sepias (Burmese expression). If the
albino gene causing these patterns affects green in the same way as
it affects black/chocolate etc, the sepia variety would have
leaf-green points and a paler, possibly yellow-green body while the
full Siamese-type expression would result in a pastel yellow-green
cat with darker points. The effect of mink would be intermediate
between these extremes.

Nor has the colour been seen in
combination with the Rex or semi-longhair (Angora) hair
type.

Note: A Dutch breeder of
British Colourpoint Shorthairs and Siamese has expressed an
interest in developing green points under the name "Greensleeves"
(a name chosen in homage to the famous "Sealsleeves" Seal Point
Siamese cats of the 1940s), although it is not known whether this
will happen in the near future.

Mrs Goddard and a number of other
Danish and American cat fanciers are working towards a wholly green
breed, tentatively named the Danish Green. The preliminary standard
calls for a cat of European Shorthair type with an even grass
green colour, although some variation will be accepted on colour
(preference given to rich, even colour) and the belly may be a
slightly paler shade due to "counter shading". Cats must not have a
yellow or grey hue to their fur. Eyes should be orange or hazel to
provide contrast with the fur colour. Olive-green fur is penalised;
it occurs due to hidden recessives and the cats may still be used
in breeding. Acceptable patterns are green self, green bicolour
(including Van pattern), green tabbies and green-and-cream/green
calico. Silver series is also accepted (Silver Tabby, Smoke,
Shaded, Tipped).

Perhaps one of the most
outstanding studs in the program to date has been "Bluegrass", a
very typey Blue European Shorthair carrying green and dilute. Bred
from Grunhilde and an undisclosed Champion Blue European Shorthair,
Bluegrass has consistently produced excellent quality kittens with
a variety of queens, including back-crossing to Grunhilde herself.
Several of his offspring - both blues carrying green and greens -
show great promise. In particular, a Bluegrass x Grunhilde cat
called "Greengrass" (full expression green carrying dilute) looks
set to follow in his sire's footsteps. Green Tea, a daughter of
Bluegrass, and half-sister to Greengrass, looks set to become an
exceptionally typey female and will hopefully produce some stunning
kittens when she reaches breeding age. To prevent excessive
inbreeding (and avoid overtyping), typey cats such as Bluegrass,
Greengrass and Green Tea will be used mostly with outcross cats to
bring in new blood.

During 2003, Absinthe Green Cattery produced several stunning green chinchillas; most notably Absinthe Green Fairy and Absinthe Green Ice; both sired by Crème-de-Menthe (cinnamon carrying green) on his half-sister (lilac carrying green). The breeders are now working the restore the proper Persian conformation which has been affected by outcrossing to introduce the green gene. The long hair of Persians seems to display green to its best effect and the same cattery has bred Greensleeves, the first green-pointed Himalayan as well as numerous self greens.

"It's easy enough to introduce the new colour," said Green Persian enthusiast Christopher-Martin Rhodes of Absinthe Green Cattery, "now we need to get back to the proper Persian type afterwards; especially the ear size and length of nose. Crème-de-Menthe is an excellent stud, but some of his sons show even greater promise as they are closer to the proper conformation as well as having excellent colour. We'd like to produce some green-cream torties, but not until we've got the type right."

Other parties are working on green
variants of existing breeds such as Persians and Green Silver
Tabby Shorthairs. Whether these will be accepted as new colour
divisions of existing breeds, or as separate breeds, will up to
individual cat fancies. Some cat enthusiasts would like to see an
all-green breed named after St Patrick, the Irish saint's day on
which green clothing is traditionally worn and even food and drink
are dyed green.

Green Smoke

Green Longhair

Interested in the green gene or
in green cats? The Danish green kitten was real, but was due to
copper contamination in local water and her colour was only
temporary. For a green breed of cat, I'm afraid you'll have to wait
for genetic mutation to catch up with imagination. Happy April Fools
Day from Moggycat & messybeast.com !

Not Photoshopped? That's right - none of these photos used Photoshop (TM); Photoshop is a proprietary package, not a verb. None of the cats were dyed. The inheritance genetics of the hypothetical recessive green gene and its modifiers, however, is fully in accordance with feline genetics.